Lung cancer represents the most common cause of cancer related deaths in both men and women with 177,000 cases diagnosed in 1996 and 158,000 deaths. Most patients present with advanced disease and aggressive therapy has been able to change their outcome only modestly. In most centers, primary radiation alone has been replaced by multimodality therapy. The simultaneous combination of chemotherapy and radiotherapy theoretically may provide a better effect on response rates and local control compared to a sequential schedule. Cisplatin is thought to be one of the active drugs in non-small cell lung cancer with a 15-20% response rate. In addition, Cisplatin is considered a radiosensitizer when administered with radiation therapy. Docetaxel is also known to act as a radiosensitizer, and several trials have reported their early results with suggestion of a potential benefit. The aims of this study are: to determine the maximal tolerated dose of Docetaxel in combination with Cisplatin and concomitant radiation therapy in the phase I component; to determine the safety and tolerability of the same combination once the maximal tolerated dose Docetaxel has been determined; and to determine the response rate, median survival and time to progression of patients with clinical stage IIIA and IIIB NSCLC with this combination.